1 files changed, 18 insertions, 1 deletions
diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
index abbd8cc4d2..928df4fa65 100644
--- a/src/validationinterface.cpp
+++ b/src/validationinterface.cpp
@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2016 The Bitcoin Core developers
+// Copyright (c) 2009-2017 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -11,9 +11,11 @@
 #include <sync.h>
 #include <txmempool.h>
 #include <util.h>
+#include <validation.h>
 
 #include <list>
 #include <atomic>
+#include <future>
 
 #include <boost/signals2/signal.hpp>
 
@@ -54,6 +56,11 @@ void CMainSignals::FlushBackgroundCallbacks() {
     }
 }
 
+size_t CMainSignals::CallbacksPending() {
+    if (!m_internals) return 0;
+    return m_internals->m_schedulerClient.CallbacksPending();
+}
+
 void CMainSignals::RegisterWithMempoolSignals(CTxMemPool& pool) {
     pool.NotifyEntryRemoved.connect(boost::bind(&CMainSignals::MempoolEntryRemoved, this, _1, _2));
 }
@@ -113,6 +120,16 @@ void CallFunctionInValidationInterfaceQueue(std::function<void ()> func) {
     g_signals.m_internals->m_schedulerClient.AddToProcessQueue(std::move(func));
 }
 
+void SyncWithValidationInterfaceQueue() {
+    AssertLockNotHeld(cs_main);
+    // Block until the validation queue drains
+    std::promise<void> promise;
+    CallFunctionInValidationInterfaceQueue([&promise] {
+        promise.set_value();
+    });
+    promise.get_future().wait();
+}
+
 void CMainSignals::MempoolEntryRemoved(CTransactionRef ptx, MemPoolRemovalReason reason) {
     if (reason != MemPoolRemovalReason::BLOCK && reason != MemPoolRemovalReason::CONFLICT) {
         m_internals->m_schedulerClient.AddToProcessQueue([ptx, this] {